The discipline of modeling has advanced only slowly compared to disciplines concerned with analyzing and solving models once they are brought into being. Structured Modeling is an attempt to redress this imbalance. Structured Modeling aims to provide a formal mathematical framework and computer-based environment for conceiving, representing, and manipulating a wide variety of models. The framework uses a hierarchically organized, partitioned, and attributed acyclic graph to represent the semantic as well as mathematical structure of a model. The computer-based environment is evolving via experimental prototypes that provide for ad hoc query, immediate expression evaluation, solving simultaneous systems, and optimization. If successful, Structured Modeling will enable model-based work to be done with greater productivity and acceptance by nonspecialists, will exploit important developments in small computers, and will cross-fertilize management science/operations research, artificial intelligence, database management, programming language design, and software engineering. This paper is an introduction and status report on a long term project. The presentation is based largely on examples; rigorous development and details are left to a series of technical reports.modeling, graphs, model design, model management systems